The utilization of hermetically sealed motor-compressor units has become increasingly prevalent in recent years in refrigeration applications wherein the motor-compressor units are employed to compress refrigerant vapor. The compressor is generally driven by an electric motor which rotates the crankshaft or driveshaft of the compressor at relatively high speeds. These hermetically sealed compressors are designed to run trouble free for the life of the motor-compressor unit.
While these hermetically sealed compressors typically do not experience any problems during their lifetime, it may be advantageous to monitor various refrigerant pressures within the refrigeration system for improved control, protection and for trouble shooting of diagnostics of both the system and the compressor should a problem occur. In an increasing number of air-conditioning or refrigeration systems, monitoring of the pressure of the refrigerant at one or several locations in the refrigeration circuit is a requirement. The pressures that are typically monitored include the suction pressure and the discharge pressure that is seen at the compressor. These pressures are traditionally sensed using a pressure sensor that is threaded into a fitting located in the suction and/or discharge refrigerant lines adjacent to the compressor. These pressure sensors are relatively expensive and unless it is essential to the proper functioning of the refrigeration system, the sensors are not installed due to financial considerations.
Assuming that a relatively inexpensive pressure sensor were made available to the refrigeration industry, most of the refrigeration systems currently being built could be improved by the incorporation of the pressure sensors. The pressure sensors could be utilized for improved control, protection and in trouble shooting of diagnostics of both the system and the compressor itself on virtually all of the refrigerant systems rather than on a limited number of systems.
The present invention provides the art with a weld-on pressure sensor for air-conditioning and refrigeration compressors. The weld-on pressure sensor is a low cost component which is easily and inexpensively welded to the shell of the compressor. The weld-on pressure sensor can be an oil filled pressure sensor, a dry type pressure sensor or a dry type pressure sensor where the shell forms the diaphragm for the pressure sensor. The weld-on pressure sensor of the present invention allows the electronics that are part of the sensing device to be placed external to the shell of the compressor and only the sensing mechanism is placed inside the hermetic shell.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.